Predictability of Equity Models

In this study, we verify the existence of predictability in the Brazilian equity market. Unlike other studies in the same sense, which evaluate original series for each stock, we evaluate synthetic series created on the basis of linear models of stocks. Following Burgess (1999), we use the “stepwise regression” model for the formation of models of each stock. We then use the variance ratio profile together with a Monte Carlo simulation for the selection of models with potential predictability. Unlike Burgess (1999), we carry out White’s Reality Check (2000) in order to verify the existence of positive returns for the period outside the sample. We use the strategies proposed by Sullivan, Timmermann & White (1999) and Hsu & Kuan (2005) amounting to 26,410 simulated strategies. Finally, using the bootstrap methodology, with 1,000 simulations, we find strong evidence of predictability in the models, including transaction costspredictability, variance ratio profile, Monte Carlo simulation, reality check, bootstrap, technical analysis

Adequação dos exames de radiologia solicitados por um departamento de emergência: um estudo retrospetivo

Imaging tests are essential for diagnosis in the emergency context and convey clinical information that is essential to assess the appropriateness of the tests and improve their interpretation. Therefore, we aimed to analyze the imaging tests requested by the Emergency Department in a district hospital.info:eu-repo/semantics/publishedVersio

Análise comparativa da qualidade vocal antes e após uma semana de trabalho em funcionários públicos com atendimento ao balcão

Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciado em Terapêutica da FalaA saúde da voz profissional tem vindo a ter cada vez mais importância à medida que mais pessoas dependem desta para exercer as suas funções profissionais. Sendo o Terapeuta da Fala o profissional de saúde responsável pela prevenção, avaliação, diagnóstico, tratamento e estudo científico da comunicação humana, este trabalho visa estudar uma população alvo específica, que são os Funcionários Públicos com atendimento ao balcão, para verificar o impacto que uma semana de trabalho tem sobre a qualidade vocal destes. Para tal, foram estudados 30 indivíduos nas repartições de finanças da região de Valpaços. Realizaram-se duas avaliações idênticas, uma antes da semana de trabalho e outra no fim desta. Posteriormente, os resultados foram comparados para verificar se existiu ou não impacto negativo na qualidade vocal destes. Através do software Praat foram avaliados os parâmetros acústicos Frequência Fundamental, Jitter, Shimmer e PHR, nas vogais /a/, /i/ e /u/, complementando-se a avaliação com os parâmetros aerodinâmicos: Tempos Máximos de Fonação nas fricativas /s/ e /z/ e respetiva relação s/z. À exceção da vogal /i/ na F0 e da vogal /u/ na PHR, no sexo feminino, onde as médias apresentaram resultados com impacto levemente positivo, todos os restantes parâmetros denotaram impacto negativo, à semelhança do que aconteceu no sexo masculino que apresentou este impacto nocivo do uso profissional da voz em todos os parâmetros avaliados. Reforça-se, então, que embora o sexo masculino tenha sido o mais atingido, toda a amostra estudada deve ser encarada como de risco para disfonia. The professional voice health is becoming more important as more people rely on their voices for their work. Being the Speech and Language Therapist health professional responsible for the prevention, assessment, diagnosis, treatment and scientific study of human communication, this work aims to study a specific target population, clerk public officials, to check the impact of a work-week on their vocal quality. To this end, we studied 30 subjects in tax offices in the region of Valpaços. There were two identical evaluations, one before the workweek and another in the end. Posteriorly, the results were compared to see if there was a negative impact on voice quality. Using Praat, acoustic measures were collected. (Fundamental Frequency, Jitter, Shimmer and HNR, on the vowels / a /, / i / and / u /), complementing the assessment with the aerodynamic parameters: Maximum Phonation Time of fricatives / s / and / z / and, respective s/z ratio. Except for the vowel / i / in F0 and vowel / u / in NHR for the females – where the averages presented results with slightly positive impact, all of the remaining parameters indicate a negative impact, as it happened in men, who presented this harmful impact of the professional voice use. This results enhance that although males have been hardest affected, this population studied can be seen as at risk for dysphonia

Numerical modeling of strain rate hardening effects on viscoplastic behavior of metallic materials

The main goal of the present work is to provide a finite strain elasticviscoplastic framework to numerically account for strain, strain rate hardening, and viscous effects in cold deformation of metallic materials. The aim is to provide a simple and robust numerical framework capable of modeling the main macroscopic behavior associated with high strain rate plastic deformation of metals. In order to account for strain rate hardening effects at finite strains, the hardening rule involves a rate dependent saturation hardening, and it accounts for linear hardening prevailing at latter deformation stages. The numerical formulation, finite element implementation, and constitutive modeling capabilities are assessed by means of decremental strain rate testing and constant strain rate loading followed by stress relaxation. The numerical results have demonstrated the overall framework can be an efficient numerical tool for simulation of plastic deformation processes where strain rate history effects have to be accounted for